Railway-traffic-controlling system



R. A. McCANN.

RAILWAY TRAFFIC CONTROLLING SYSTEM.

APPLICATION FILED JUNE 26, 1919.

1,363,257. Patented Dec. 28, 1920.

INVENTOR QM alm/n,

ATTORNEY UNITED STATES.

PATENT OFFICE.

RONALD A. MCOANN, 0F SWISSVALE, PENNSYLVANIA, ASSIGNOR TO UNION SWITCH &SIGNAL COMPANY, OF SWISSVALE, PENNSYLVANIA, A CORPORATION OF PENN-SYLVANIA.

RAILWAY-TRAFFIC-CONTROLLING SYSTEM.

.3 ,3()v= d5 2 I Appllcatlon June 26,

To all whom 272, may concem Be it known that I, RONALD A. MCGANN, acitizen of the United States, residing at Swissvale, in the county ofAllegheny and State of Pennsylvania, have invented certain new anduseful Improvements in Railway-Traflic-Controlling Systems, of which thefollowing is a specification.

My invention relates to railway traffic controlling systems, andparticularly to systems of the type wherein alternating current orcurrents are supplied to the track rails, and the cars or trains areprovided with governing apparatus which is controlled by such current orcurrents in the rails.

In one system of the type mentioned, it has been proposed to employ theusual track circuit current, that is, the current which energizes thetrack relays, as one of the currents for controlling the train-carriedgoverning apparatus, the train governing apparatus being controlled bythis current through the medium of receiving appliances at the front endof the train. When this is done, it is obvious that the source of trackcircuit current must always be connected across the track rails ahead ofa train.

in the case of a double track railroad wherein tra'liic on each tracknormally moves in one direction only, this requirement is readily met inso far as movements in the normal direction are concerned, because thesource of track circuit current for each section of track can then beconnected across the rails at the exit end of the section, this being infact in accordance with standard practice in automatic block signaling.On roads of this kind, however, it is sometimes necessary for trains tomove in opposition to the normal direction of traffic, and in suchinstances with only the trackway apparatus thus far mentioned the trainwould not receive track circuit current. One feature of my invention isthe provision of means located in the trackway and set into operation bya train moving against the normal direction of traffic for connecting anan iary source of track circuit current across the rails of each sectionat what is normally the entrance end of the section.

In systems of this type it has also been proposed to supply a second, orline circuit current, to the track rails in such man nor that it flowsthrough the two rails in Specification of Letters Patent.

Patented Dec. 28, 1920.

1919. Serial No. 306,776.

multiple, which current coacts with the track circuit current to controlthe train governing apparatus. This line circuit current is supplied toonly the rear portion of each section when the section next in advanceis occupied, and so it follows that when a train moving against thenormal direction of traflic enters a section it will not receive linecircuit current until the rear end of the train has passed out of theadjacent section. Another feature of my invention is the provision ofmeans for supplying line circuit current to the rails of a sectionthroughout the entire section, re gardless of conditions in any othersection, when a train moving against the normal direction of trafficenters the section.

I will describe one form of trackway apparatus embodying my invention,and will then point out the noval features thereof in claims.

The accompanying drawing is a diagrammatic View showing one track of adouble track railway equipped with trackway apparatus embodying myinvention.

Referring to the drawing, the reference characters 2 and 2 designate thetwo traffic rails of a railway track F over which traffic normally movesonly in the direction in dicated by the arrow. These railsare divided byinsulated joints 3 into a plurality of successive sections, of whichonly two complete sections BC and CD are shown in the drawing.

Each track section is provided with a track circuit comprising two trackrelays and a source of track circuit current. Considering section CD,for example, two track relays T and T are connected across the trackrails adjacent the exit and entrance ends of the section respectively,and the secondary of a transformer E is also connected across the railsof this section adjacent the exit end. The primary of transformer E isconnected with the secondary of a transformer U through a pole-changeroperated as hereinafter explained. The primary of transformer U as wellas the primaries of certain other transformers U and U, are connectedwith a suitable source of alternating current which is not shown in thedrawing. The track relay T at the exit end of the section is constantlyconnected with the rails of the section, but the track relay T at theentrance end is at times disconnected from the rails by a re lay J andthe secondary of a transformer H is then connected across the railsthrough the front contacts of relay J In other words, track relay T ortransformer H is connected with the rails of section C-D adjacent theentrance end thereof, according as relay J is deenergized or energized.The primary of transformer H is connected with the secondary oftransformer U. The connection between the secondary of transformer E andthe track rails includes a back contact 46 of a relay K so that whenthis relay is energized transformer E is disconnected from the rails ofthe section. The control of relays K and J will be explainedhereinafter.

Each track section is provided with track circuit apparatus similar tothat just described for section G-D.

Located adjacent the entrance end of each section is a signal which isdesignated by the reference character S with an exponent correspondingto the location, each of which signals is adapted to indicate stop,caution and proceed. Each signal is controlled by the track relay at theentrance end of the corresponding section. Considering signal S,forexample, the caution indication circuit is from the secondary oftransformer U through wires 4, 5 and 6 right-hand point of contact 7 oftrack relay T, wire 15, operating mechanism of signal S wire 9, righthand point of 'contact ll of track relay T, and wires 12 and 13 to thesecondary of transformer U The proceed indication circuit for thissignal is from the secondary of transformer U through. wires 4, 5 and 6,left-hand point of contact 7, wire 8, operating mechanism of signal Swire, 9, righthand point of contact 11, and wires 12 and 13 to thesecondary of transformer U It will be seen, therefore, that signal Swill indicate proceed when track relay T is energized in such directionthat'its contacts 7 and, 11 are swung to the left, which direction Iwill term the normal direction of energization of this relay, and thatthis signal will indicate caution when track relay T? is energized inthe other or reverse direction. Relay T is energized in normal directionwhen. track circuit current of normal polarity is supplied to the railsof section (1-D by transformer E lWhen current of reverse polarity issupplied to the rails of this section by transformer E track relay T isenergized in reverse direction, so that its contacts 7 and 1.1 are swungto the left, causing signal S to indicate caution.

The polarity of the current supplied to the track circuit for sectionC-D is controlled by pole-changer P which is operated by signal S insuch mannerthat the'track circuit current is of normal polarity whenvsignal S indicates proceed or caution, and

of reverse polarity when this signal indicates stop.

Although as here shown track relay T comprises only one winding, it is,of course, understood that inasmuch as this relay is operated byalternating current, it comprises a second winding constantly suppliedwith current from either .transformer H or transformer U This secondwinding is omitted from the drawing for the purpose of simplification.The same thing is true as to relays T and T The control of the signaland of the polarity of the track circuit current for each sec tion isthe same as for section CD.

Line circuit current is supplied to the track rails of each sectionthrough the medium of resistances 20, 21 and 22, which are connectedacross the rails of the section at the entrance end of the section,intermediate point in the section, and the exit end of the section,respectively. Again considering section C-D specifically, line circuitcurrent is constantly supplied to the rails between resistances 20 and21 when the section is occupied, the circuit being from the left-handterminal of the secondary of transformer F through contact 16 of relayT" wire 17 to the middle point of resistance 20, thence through the tworails 2 and 2 in multiple to resistance 21, and from the middle point ofthis resistance through wires 18 and 19 to the second ary of transformerF The primary of transformer F is connected with the secondary oftransformer U Contact 16 is closed only when relay T is deenergized,and, con sequently, line circuit current is supplied to the circuit justtraced only when section -D is occupied bya train, but at such timesthis circuit is always closed regardless of traliic conditions inadvan'ceof the section. Line circuit current is also supplied at timesto the rails of section CD between resistances 21 and 22, the normalcircuit being from the left-hand terminal of the secondary oftransformer G through wires and 2 contact 25 operated by signal S, wire26 to the middle point of resistance 22, rails 2 and 2 in multiple toresistance 21, and from the middle pointof this resistance through wires18 21116142 to the secondary of transformer G Contact 25 is closed whensignal S -indicates proceed or caution, but open when this signalindicates stop. It will be seen, therefore, that so far as the circuitjust traced is concerned, line circuit current is supplied to section CDbetween that when relay K is energized, line circuit current is suppliedto the rails of section Cl) between resistances 21 and 22 regardless ofthe position of signal S The line circuit apparatus for each section isthe same as that just explained for section C-D.

Again considering section C-D, relays K and J D are provided with apick-up circuit, which is as follows: from the left-hand terminal of thesecondary of transformer U through wires 4, 5, 30, 31 and 31, contact 10operated by signal S wire 32, winding of relay J wire 33, back contact34: of track relay T wire 35, winding of relay K and wire 36 to thesecondary of transformer U It will be seen that this circuit is closedonly when contact 10 and track relay contact 3 1 are simultaneouslyclosed. It follows, therefore, that the circuit will not be closed whena train moves in the direction indicated by the arrow, because contact10 will open immediately upon the entrance of such a train into section(i-D, whereas track relay contact 34: will not close until the train hasproceeded a considerable distance into the section. \V hen a trainmoving in the direction opposite to that indicated by the arrow entersthe section, however, it will immediately open track relay T so thatcontact 34 of this relay will close before signal-operated contact 10has time to open. A train moving in this direction, therefore, willcause relays K and J to become energized. As soon as relay J closes, abranch for this circuit around contact 10 is closed, which branch isfrom wire 30, through, wire 39, contact 40 of relay J and wire 11 towire 32. It follows, therefore, that when relays K and J have oncebecome closed, they will remain closed as long as track relay contact34c remains closed, that is, until the entire train has passed out ofsection C-D.

Before explaining the operation of the system as a whole it should bepointed out that the trackway apparatus here shown is intended forcooperation with train-carried governing apparatus which operates in thefollowing manner: When the train is on a portion of track which issupplied with track circuit current of normal. polarity and also withline circuit current, the governing apparatus permits the train totravel at high speed, such as miles per hour. When the portion of trackoccupied by the train is supplied with track circuit current of reversepolarity and also with line circuit current. the governing apparatusprevents the train from proceeding at more than an intermediate speed.such as 35 miles per hour. but when the train enters a portion of tracl:from which the supply of either track circuit or line circuit current isdiscontinued, the governing apparatus prevents the train from proceedingat more than a low speed such as 10 miles per hour. One form ofgoverning apparatus which will cooperate in this manner with thetrackway apparatus here shown, is illustrated and described in anapplication filed in the United States Patent Oflice by Lloyd V. Lewison Nov. 1, 1918, Serial No. 263607, for railway traflic controllingsystems.

The operation of the entire apparatus is as follows:

I will first assume that the stretch of track shown in the drawing isunoccupied, and that a train moving in the direction indicated by thearrow enters the stretch. As this train enters section CD, itdeenergizes track relay T so that contacts 7, 11 and 16 move to theirintermediate positions. The opening of contacts 7 and 11, of course,causes signals S to move to the stop position. The movement of contact16 to its intermediate position closes the line circuit for the rearportion of section 0-D, so that line circuit current is supplied to therails of this section between resistances 20 and 21. Inasmuch as signalS is in the proceed position, track circuit current of normal polarityis supplied to the rails of section C-D from transformer E Line circuitcurrent is also supplied to the rails of this section betweenresistances 21 and 22, because signal S is in the proceed position. Itfollows, therefore, that the train can proceed through section C-D at 65miles per hour or less. The operation of the apparatus in section B-C isthe same as that of the apparatus in section C-D, and hence it will beunderstood without further explanation.

I will now assume that while the first train is in section B-C, a secondtrain enters section C-D. Signal S is then at stop, so that trackcircuit current of reverse polarity is supplied to the rails of section(l-D. Contact 25 operated by signal S is open, so that line circuitcurrent is not supplied to section C-D between resistances 21 and 22. Asthe second train passes the point D, it will receive line circuitcurrent and it will. also receive track circuit current of reversepolarity, so that this train will incur a brake application if itexceeds a speed of miles per hour while between resistances 20 and 21..After passing resistance 21, the train will cease to receive linecircuit current and consequently it will incur a brake application if itexceeds 10 miles per hour. If this second train passes signal S whilethe latter is still at stopv it will fail to receive track circuitcurrent because such current is shunted by the wheels and axles of thefirst train, and consequently, the second train will still be compelledto proceed at a speed not exceeding 10 miles per hour.

I will now assume that, owing to an emergency condition, it is necessaryfor a train to pass over the stretch of track shown in the drawing inthe direction opposite to that indicated by the arrow, and I willfurthermore assume that such train is in section BC and is about toenter section CD. Signal S is, of course, at stop, so that signal S isin the caution position. As this train enters section CD, it immediatelyopens track relay T and since contact 10 is still closed, relays K and Jwill become energized. Relay K then disconnects transformer E from thetrack-rails; whereas re lay J disconnects track relay T from the rails,and connects transformer H with the rails, at the right-hand end of thesection. Relay K also closes the shunt around contact 25 in the linecircuit for the portion of the section between resistances 21 and 22, sothat line circuit current is supplied to this part of thesection. Trackrelay T of course becomes decnergized, so that line circuit current isalso supplied to the section between resistances20 and 21. Track circuitcurrent is now supplied to the rails from transformer H and the currentthus supplied is of: normal polarity, so that the train can proceedthrough section C D at full'speed, that is, at 65 miles per hour orless, without incurring a brake application. When the rear end' of thistrain passesout of section 0 1), track relay T will become energized byvirt-ue of the current supplied to the rails by transformer H Theclosing of track relay T will open the circuit for relays K and J sothat these relays will then become deenergized. The opening of relay J Dwill disconnect transformer H from, and connect relay J with, the railsof the section; the opening of relay K will again connect transformer Ewith the track rails. Relay T will then become energized by virtue ofcurrent from transformer E so that signal S will return to the proceedposition (or to the caution position if section B-C is occupied).

It will be noted that an impedance as is interposed between track rail 2and the winding of track relay T When relay K is energized, thisimpedance is shunted by alow resistance path which passes from point 45,through wire 45, front point of contact 46 of relay K and wire 49 topoint 45. The impedance as is, therefore, shunted out of the trackcircuit when relay K is energized. The reason for this is as follows:

FVhen the track circuit for section C-D is in normal condition, that is,when the parts areas shown in the drawing, transformer E is connectedacross the rails at the same point as track relay T The impedance 43'isdesirable at such time in order to avoid over-energization of relay Tand under-energization of relayT; When, how- -undesirable to leave theimpedance 4:3 in

ever, the track circuit arrangement is reversed; that is, whentransformer E is disconnected from the rails and transformer H isconnected with the rails, it would be serieswithrelay T because an undueamount of energy would then be required from transformer H to causetrack relay T toclose after atrain moving toward the right passes out ofthe section. A low resistance path around this impedance is provided,therefore, toshunt out the impedance while the track circuit isreversed, with the result that only the normal amount of energy isrequiredfrom transformer H to energize relay T when the train movingtoward the right leaves the section.

Although in certain of the accompanying claimsI have referredspecifically to track section C -D, it is understood that this is doneonly for the sake of clearness, and that all such claims are readableequally well on the apparatus shown in track section B-C.

AlthoughI have herein shown and described only one. form of trackwayapparatus embodying my invention, it is understood that various changesand modifications may be made therein within the scope ofthe appendedclaims without departing from the spirit and scope of my invention. 9

Having thus described my invention, what I claim is: i

1. In combination, a section of railway track over which trafficnormally moves in one direction only, a track relay normally connectedacross the rails adjacent the entrance end of the section and a sourceof current located adjacent the same end, a second track relayconstantly connected across the rails, adjacent the exit end of thesection and a second source of current normally connected across therails adjacent the exit end ofcthe section; a signal located adjacentthe entrance end of said section and controlled by the track relay at 11 0 the same end; and means controlled by said signal and by said secondtrack relay and operating when a train moving in opposition to thenormal direction of trafiic enters said section to' disconnect saidfirst 11 5 track relay from the track rails, to connect said firstsource of current with the track rails, and to disconnect said secondsource of current from the track rails.

Q. In combination, a section of railway 1'20 track over which trafiicnormally moves in one direction only, two track relays T and T adjacentthe entrance. and exit ends of said section respectively, the latterrelay being constantly connected with the 125 track rails, a signal Sfor said section controlled bysaid track relay T two sourcesof'alternating current H and'E adjacent the" entrance and exit ends ofsaid section respectively, the latter being normally con- 1370 nectedwith the rails of said section, a relay J for connecting track relay Tor source H with the track rails according as relay J is deenergized orenergized, a relay K for disconnecting source E from the track railswhen the relay is energized, a contact 10 operated by signal S andclosed or open according as the signal indicates proceed or stop, acircuit including relays J and K, a back contact of track relay '1 andsaid contact 10, and a branch for said circuit around contact 10 andincluding a front contact of relay J In combination, a section ofrailway track over which tra'liic normally moves in one direction only,two track relays T and T adjacent the entrance and exit ends of saidsection respectively, the latter relay being constantly connected withthe track rails, a signal S for said section controlled by said trackrelay T two sources of alternating current H and E adjacent the entranceand exit ends of said section re spectively, the latter being normallyconnected with the rails of said section, a relay J for connecting trackrelay T or source H with the track rails according as relay J isdeenergized or energized, a relay K for disconnecting source E from thetrack rails when the relay is energized, and means controlled by saidsignal and by said track relay T and operating when a train moving inopposition to the normal direction of traffic enters said section toenergize said relays K and J and to keep them energized until such trainleaves the section.

4. In combination, a section of railway track over which trafficnormally moves in one direction only, a track relay and a source ofcurrent at the entrance end of said section the former being normallyconnected with the rails of the section, a second source of currentconnected with the rails of said section at the exit end, a signallocated adjacent the entrance end of said section and controlled by saidtrack relay, and means controlled by said signal and operating when atrain moving in opposition to said normal direction of traiiic entersthe section to disconnect said track relay from the rails of the sectionand connect said first-mentioned source of current with said rails.

5. In combination, a section of railway track over which trafficnormally moves in one direction only, a track relay and 'a source ofcurrent at the entrance end of said section the former being normallycon nected with the rails of the section, a second source of currentconnected with the rails of said section at the exit end, a signallocated adjacent the entrance end of said section and controlled by saidtrack relay, a normally deenergized relay J arranged when energized todisconnect said track relay from the rails of said section and toconnect said first-mentioned source of current with said rails, meanscontrolled by said signal and operating when a train moving inopposition to said normal direction of tratiic enters said section toenergize said relay J and m ans for keeping said latter relay energizeduntil such train leaves the section.

6. In combination, a section of railway track over which trafficnormally moves in one direction only, a source of current connected withthe track rails adjacent the exit end of the section, ,a second sourceof current adjacent the entrance end of the section but normallydisconnected from the rails, a signal located adjacent the entrance endof said section and controlled by trafiic conditions in the section, andmeans controlled by said signal and operating when a train moving inopposition to said normal direction of trafiic enters the section toconnect said second source of current with the rails of the section.

7. In combination, a section of railway track over which trafiicnormally moves in one direction only, a line circuit including the twotrack rails in multiple from the entrance end of the section toanintermediate point in the section, means for supplying current to saidcircuit, a second line circuit including the two track rails in multiplefrom said intermediate point to the exit end of the section, meanscontrolled by trafic conditions in advance of said section for supplyingcurrent to said second line circuit, and means controlled by a trainentering said section in opposition to the normal direction of trafficfor supplying cur rent to said second line circuit regardless of trailicconditions extraneous to the section.

8. In combination, a section of railway track over which trafficnormally moves in one direction only, a line circuit including the twotrack rails in multiple from the entrance end of the section to anintermediate point in the section, means for supplying current to saidcircuit, a second line circuit including the two track rails in multiplefrom said intermediate point to the exit end of the section, meanscontrolled by traiiic conditions in advance of said section forsupplying current to said second line circuit, and means controlled by atrain entering said section in opposition to said normal direction oftrafiic for removing said last-mentioned means from control by trafficconditions in advance of the section.

9. In combination, a section of railway track over which trafficnormally moves in one direction only, a line circuit including the twotrack rails in multiple from the entrance end of the section to anintermediate point in the section, means for supplying current to saidcircuit, a second line circuit including the two track railsin multiplefrom said intermediate point to the exit end of the section, meanscontrolled by traffic conditions in advance of said section forsupplying current to said second line circuit, a normally deenergizedrelay, means cont-rolled by said relay when energized for removing saidlast-mentioned means from control by trafiic conditions in advance ofthe section, and means controlled by a train entering said section inopposition to said normal direction of traffic for energizing saidrelay.

10. In combination, a section of railway track over which traflicnormally moves in one direction only, means for supplying line circuitcurrent to the two rails of said section in multiple from the entranceend to an intermediate point in the section or from the entrance end tothe exit end according to traffic conditions in advance of the section,and means controlled by a train entering said section in opposition tothe normal direction of traflic for removing said means from control bytrafiic conditions in advance of the section and supplying line circuitcurrent to the rails throughout the length of the section.

11. In combination, a railway track over which trafiic normally moves inone direction only, means for dividing said track into a plurality ofsuccessive sections, a signal for each section located adjacent theentrance end of the section, means for each section for supplying linecircuit current to the two track rails of the section in multiple fromthe entrance end of the section to an intermediate point in the sectionregardless of traffic conditions in advance of the section, means foreach section controlled by the signal for the section next in advancefor supplying line circuit current to the two track rails of the sectionin multiple from said intermediate point to the exit end of the sectionwhen said signal indicates proceed but not when said signal indicatesstop, and means for each section controlled by a train entering thesection in. opposition to the normal direction of traiiic for removingsaid last-mentioned means from control by the signal for the section inadvance.

7 12. In combination, a railway track over which traffic normally movesin one direction only, means for dividing said track into a plurality ofsuccessive sections, a signal for each section located adjacent theentrance end of the section, means for each section for supplying linecircuit current to the two track rails of the section in multiple fromthe entrance end of the section to an intermediate point in the sectionregardless of trafiic conditions in advance of the section, means foreach section controlled by the signal for the section next in advancefor supplying line circuit current to the two track rails of the sectionin multiple from said intermediate point to the exit end of the sectionwhen said signal indicates proceed but not when said signal indicatesstop, a normally deenergized relay for each section, means controlled bysaid relay when energized for removing said last-mentioned means fromcontrol by the signal for the section next inadvance, and means for eachsection controlled by a train entering the section in opposition to saidnormal direction of traflic for energizing the relay for such section.

13. In combination, a railway track over which traffic normally moves inone direction only, means for dividing said track into a plurality ofsuccessive sections, a signal for each section located adjacent theentrance end thereof, a line circuit for each section including thetrack rails of the section in multiple from the entrance end of thesection to an intermediate point in the section, means for supplyingcurrent to said circuit regardless of trafiic conditions in ad vance ofthe section, a second line circuit for each section including the trackrails of the section in multiple from said intermediate point to theexit end of the section and ineluding a contact operated by the signalfor the section next in advance which contact is closed when the signalindicates proceed but not when the signal indicates stop, a branch forsaid second line circuit for each section around said signal-operatedcontact, and means for each section controlled by a train entering thesection in opposition to the normal direction of traffic for closing thebranch for the second line circuit for such section.

14:. In combination, a section ofrailway track over which trafficnormally moves in one direction only, a signallocated adjacent theentrance end of said section and governing trafiic through the section,a track circuit for said section including a track relay locatedadjacent the exit end of the section, means for supplying line circuitcurrent to the two track rails of said section in multiple from theentrance-end of the section to an intermediate point in the section orfrom the entrance end of the section to the exit end of the sectionaccording to trafiicconditions in advance of the section, and meanscon-' trolled by said signal and by said track relay and operating whena train moving in opposition to said normal direction of traiiic enterssaid section for removing said means from control by traflic conditionsin advance of the section.

15. In combination, a section of railway track over which traflicnormally moves in one direction only, a source of current normallyconnected with the track rails adjacent the exit end of the section, asecond source of current adjacent the entrance end of the section, atrack relay connected with the rails adjacent the exit end of thesection, and a second track relay normally connected with the railsadjacent the entrance end of the section, a signal located adjacent theentrance end of said section and controlled by said second track relay,means controlled by traffic conditions in advance of said section forsupplying line circuit current to the two track rails in multiple fromthe entrance end of the section to an intermediate point in the sectionor from the entrance end to the exit end of the section; and meanscontrolled by the first track relay and by said signal and operatingwhen a train moving in opposition to the normal direction of traflicenters the section to disconnect said second track relay from the rails,and to connect said second source of current with the rails adjacent theentrance end of the section and to supply line circuit current to thetwo track rails in multiple throughout the entire section regardless oftraflic conditions in advance of the section.

16. In combination, a section of railway track over which trafiicnormally moves in one direction only, a line circuit extending from theentrance end of the section to an intermediate point in the section andincluding a source of alternating current, a second line circuitextending from said intermediate point to the exit end of the section,means controlled by traffic conditions in ad Vance of said section forsupplying current to said second line circuit, and means controlled by atrain entering said section in opposition to the normal direction ofti'afiic for supplying current to said second line circuit regardless oftraffic conditions extraneous to the section.

17. In combination, a section of railway track over which traflicnormally moves in one direction only, a line circuit extending from theentrance end of the section to an intermediate point in the section andincluding a source of alternating current, a second line circuitextending from said intermediate point to the exit end of the section,means controlled by traffic conditions in advance of said section forsupplying current to said second line circuit, and means controlled by atrain entering said section in opposition to said normal direction oftraffic for removing said last-mentioned means from control by trafficconditions in advance of the section.

18. In combination, a section of railway track over which traflicnormally moves in one direction only, a line circuit extending from theentrance end of the section to an intermediate point in the section andincluding a source of alternating current, a second line circuitextending from said intermediate point to the exit end of the section,

means controlled by trafiic conditions in advance of said section forsupplying current to said second line circuit, a normally deenergizedrelay, means controlled by said relay when energized for removing saidlastmentioned means from control by trafic conditions in advance of thesection, and means controlled by a train entering said section inopposition to said normal direction of ti-allic for ener izing saidrelay.

19. In combination, a section of railway track over which traificnormally moves in one direction only, means for supplying line circuitcurrent to said section from the entrance end to an intermediate pointin the section or from the entrance end to the exit end according totraflic conditions in ad- Vance of the section, and means controlled bya train entering said section in opposition to the normal direction oftra'fiic for removing said means from control by traffic conditions inadvance oI the section and supplying line circuit current to saidsection throughout the length 01": the section.

20. In combination, a railway track over which trafiic normally moves inone direc tion only, means for dividing said track into a plurality ofsuccessive sections, a signal for each section located adjacent theentrance end of the section, means for each section for supplying linecircuit current to the section from the entrance end of the section toan intermediate point in the section regardless of trafiic conditions inadvance of the section, means for each section controlled by the signalfor the section next in advance for supplying line circuit current tothe section from said intermediate point to the exit end of the sectionwhen said signal indicates proceed but not when said signal indicatesstop, and means for each section controlled by a train entering thesection in opposition to the normal direction of traffic for removingsaid last-mentioned means from control by the signal for the section inadvance.

21. In combination, a railway track over which traiiic normally moves inone direc tion only, means for dividing said track into a plurality ofsuccessive sections, a signal for each section located adjacent the entrance end of the section, means for each section for supplying linecircuit current to the section from the entrance end of the section toan intermediate point in the section regardless of traflic conditions inadvance of the section, means for each section controlled by the signalfor the section next in advance for supplying line circuit current tothe section from said intermediate point to the exit end of the sectionwhen said signal indicates proceed but not when said signal indicatesstop, a normally deenergized relay for each section, means controlled bysaid relay when energized for removing said last-mentioned means fromcontrol by the signal for the section next in advance, and means foreach section controlled by a train entering the section in opposition tosaid normal direction of traffic for energizing the relay for suchsection.

22. In combination, a railway track over which traffic normally moves inone direction only, means for dividing said track into a plurality ofsuccessive sections, a signal for each section located adjacent theentrance end thereof, a line circuit for each section extending from theentrance end of the section to an intermediate point in the section,means for supplying current to said circuit regardless of trafiicconditions in advance of the section, a second line circuit for eachsection extending from said intermediate point to the exit end of thesection and including a contact operated by the signal for the sectionnext in advance which contact is closed when the signal indicatesproceed but not when the signal indicates stop, a branch for said secondline circuit for each section around said signal-operated contact, andmeans for each section controlled by a train entering the section inopposition to the normal direction of traffic for closing the branch forthe secondline circuit for such section.

23. In combination, a section of railway track over which trafficnormally moves in one direction only, a signal located adjacent theentrance end of said section and governing trafiic through the section,a track circuit for said section including a track relay locatedadjacent the exit end of the section, means for supplying line circuitcurrent to said section from the entrance end of the section to anintermediate point in the section or from the entrance end of thesection to the exit end of the section according to traffic conditionsin advance of the section, and

means controlled by said signal and by said track relay and operatingwhen a train moving in opposition to said normal direction of trafficenters said section for removing said means from control by traflicconditions in advance of the section.

24. In combination, a section of railway track over which trafficnormally moves in one direction only, a source of current normallyconnected with the track rails adj acent the exit end of the section, asecond source of current adjacent the entrance end of the section, atrack relay connected with the rails adjacent the exit end of thesection, and a second track relay normally connected with the railsadjacent the entrance end of the section, a signal located adjacent theentrance end of said section and controlled by said second track relay,means controlled by traffic conditions in advance of saidsection forsupplying line circuit current to the section from the entrance end ofthe section to an intermediate point in the section or from the entranceend to .the exit end of the section; and means controlled by the firsttrack relay and by said signal and operating when a train moving inopposition to the normal direction of traffic enters the section todisconnect said second track relay from the rails, and to connect saidsecond source of current with the rails adjacent the entrance end ofthesection and to supply line circuit current to the section throughoutthe entire section regardless of traffic conditions in advance of thesection.

In testimony whereof I aflix my signature in presence of two witnesses.

A. HERMAN WEGNER, J. H. STULL.

